1. Field of the Invention
The present invention relates to a mold for compression molding a resin article. More particularly, the present invention relates to a mold for compression molding a resin into a molded resin article, which mold can produce a molded resin article while preventing squeeze-out of the resin melt from the mold and leaving no air in the mold cavity during molding.
2. Description of the Related Art
As a method for compression molding a resin into a molded article, there is known a method comprising supplying a resin melt to a cavity formed in a mold consisting of male and female mold portions and closing the male and female mold portions to mold the resin.
In the conventional method, the upper (female) and lower (male) molds 21 and 22 are once opened and then closed to mate with each other in the vertical direction V as shown in FIG. 1A, whereby a cavity 23 is formed therebetween and the resin melt 24 is compressed. Therefore, a dimensional accuracy of the molds 21 and 22 is strictly defined. In particular, a mold edge 21a of the upper mold 21 and a mold edge 22a of the lower mold 22 are so designed that no gap is formed in the horizontal direction H or the length L' of the mated part is made unnecessarily long (see. FIG. 1B) whereby the excess resin melt is squeezed out from the end of the edges 21a and 22a so that, as shown in FIG. 2B, the molded article 25 has an irregular shape.
However, if the size accuracy is too strict or the length L' is too long, air 26 can be trapped in the cavity 23 as shown in FIG. 1B, so that, as shown in FIG. 2A, the molded article 27 has an underfilld part 28.
In addition, the edges 21a and 22a may engage each other and may be damaged.